login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A034887 Number of digits in 2^n. 20
1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The sequence consists of the positive integers, each appearing 3 or 4 times. - M. F. Hasler, Oct 08 2016

LINKS

T. D. Noe, Table of n, a(n) for n = 0..10000

Eric Weisstein's World of Mathematics, Mersenne Number

FORMULA

a(n) = floor(n*log(2)/log(10)) + 1. E.g., a(10)=4 because 2^10 = 1024 and floor(10*log(2)/log(10) + 1 = 3 + 1 = 4. - Jaap Spies, Dec 11 2003

a(n) = A055642(2^n) = A055642(A000079(n)).

MAPLE

seq(floor(n*ln(2)/ln(10))+1, n=0..100); # Jaap Spies, Dec 11 2003

MATHEMATICA

Table[Length[IntegerDigits[2^n]], {n, 0, 100}] (* T. D. Noe, Feb 11 2013 *)

IntegerLength[2^Range[0, 80]] (* Harvey P. Dale, Jul 28 2017 *)

PROG

(Magma) [#Intseq(2^n): n in [0..100] ]; // Vincenzo Librandi, Jun 23 2015

(PARI) A034887(n)=n*log(2)\log(10)+1 \\ or: { a(n)=#digits(1<<n) }. - M. F. Hasler, Oct 08 2016

CROSSREFS

Cf. A055253, A055254.

Cf. A000079, A055642.

See A125117 for the sequence of first differences.

Sequence in context: A319951 A222642 A081832 * A192543 A082964 A285524

Adjacent sequences: A034884 A034885 A034886 * A034888 A034889 A034890

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 10:03 EST 2022. Contains 358630 sequences. (Running on oeis4.)